1. Field of the Invention
The invention relates to a lifting assembly for pre-stressed precast concrete tees.
2. Description of the Related Art
It is known to utilize pre-stressed concrete building components, such as single and double tees, that are precast prior to shipment and installation on a construction project. A precast concrete tee can be very heavy, and may be cast and removed from a mold, placed on a transporting vehicle, and installed at the construction site as a single unit using cranes, gantries, helicopters, or other equipment suitable for lifting heavy objects.
To facilitate the attachment of hooks, cables, chains, and the like, for moving such loads, steel lifting anchors may be integrated into the concrete web(s) and center portion of the flange during casting of the tees. FIG. 1A illustrates a known square wire lifting anchor 10 having an inverse vee-shaped head 12, transitioning to a pair of generally parallel legs 14, in turn transitioning to a pair of laterally disposed feet 16 formed by bending an end of each leg 14 so that the feet 16 are generally orthogonal to the legs 14 and parallel to each other. FIG. 1C is a variation of the square wire lifting anchor of FIG. 1A where prime numerals in FIG. 1C are used to designate like parts of the lifting anchor of FIG. 1A. The only difference between the anchors of FIGS. 1A and 1C is that the feet 16′ of FIG. 1C are bent orthogonal to the legs 14′ but lie in the plane of the inverse vee-shaped head 12′ and the parallel legs 14′, whereas the feet 16 of FIG. 1A are transverse to the plane of the inverse vee-shaped head 12 and parallel legs 14
FIG. 1B illustrates a known round wire lifting anchor 20 having an inverse vee-shaped head 22, transitioning to a pair of generally parallel legs 24, in turn transitioning to a pair of laterally disposed feet 26 formed by bending an end of each leg 24 into a hook-shape so that the feet 26 are in generally opposed disposition.
The anchor feet of FIGS. 1A-1C may interfere with the positioning of pre-stressing strands, and may extend too near an outside face of the tee, potentially impacting the pull-out strength of the anchor and the bending resistance of the tee. A need exists for a lifting anchor for pre-stressed precast concrete tees that may solve the above-described problems with known tee anchors.